Remove tools again. Should have done it with svn merge --reintegrate

1 files changed, 0 insertions, 1092 deletions

diff --git a/tools/plink/sshbn.c b/tools/plink/sshbn.c
deleted file mode 100644
index e9ff0cde4..000000000
--- a/tools/plink/sshbn.c
+++ /dev/null
@@ -1,1092 +0,0 @@
-/*

- * Bignum routines for RSA and DH and stuff.

- */

-

-#include <stdio.h>

-#include <assert.h>

-#include <stdlib.h>

-#include <string.h>

-

-#include "misc.h"

-

-/*

- * Usage notes:

- *  * Do not call the DIVMOD_WORD macro with expressions such as array

- *    subscripts, as some implementations object to this (see below).

- *  * Note that none of the division methods below will cope if the

- *    quotient won't fit into BIGNUM_INT_BITS. Callers should be careful

- *    to avoid this case.

- *    If this condition occurs, in the case of the x86 DIV instruction,

- *    an overflow exception will occur, which (according to a correspondent)

- *    will manifest on Windows as something like

- *      0xC0000095: Integer overflow

- *    The C variant won't give the right answer, either.

- */

-

-#if defined __GNUC__ && defined __i386__

-typedef unsigned long BignumInt;

-typedef unsigned long long BignumDblInt;

-#define BIGNUM_INT_MASK  0xFFFFFFFFUL

-#define BIGNUM_TOP_BIT   0x80000000UL

-#define BIGNUM_INT_BITS  32

-#define MUL_WORD(w1, w2) ((BignumDblInt)w1 * w2)

-#define DIVMOD_WORD(q, r, hi, lo, w) \

-    __asm__("div %2" : \

-	    "=d" (r), "=a" (q) : \

-	    "r" (w), "d" (hi), "a" (lo))

-#elif defined _MSC_VER && defined _M_IX86

-typedef unsigned __int32 BignumInt;

-typedef unsigned __int64 BignumDblInt;

-#define BIGNUM_INT_MASK  0xFFFFFFFFUL

-#define BIGNUM_TOP_BIT   0x80000000UL

-#define BIGNUM_INT_BITS  32

-#define MUL_WORD(w1, w2) ((BignumDblInt)w1 * w2)

-/* Note: MASM interprets array subscripts in the macro arguments as

- * assembler syntax, which gives the wrong answer. Don't supply them.

- * <http://msdn2.microsoft.com/en-us/library/bf1dw62z.aspx> */

-#define DIVMOD_WORD(q, r, hi, lo, w) do { \

-    __asm mov edx, hi \

-    __asm mov eax, lo \

-    __asm div w \

-    __asm mov r, edx \

-    __asm mov q, eax \

-} while(0)

-#else

-typedef unsigned short BignumInt;

-typedef unsigned long BignumDblInt;

-#define BIGNUM_INT_MASK  0xFFFFU

-#define BIGNUM_TOP_BIT   0x8000U

-#define BIGNUM_INT_BITS  16

-#define MUL_WORD(w1, w2) ((BignumDblInt)w1 * w2)

-#define DIVMOD_WORD(q, r, hi, lo, w) do { \

-    BignumDblInt n = (((BignumDblInt)hi) << BIGNUM_INT_BITS) | lo; \

-    q = n / w; \

-    r = n % w; \

-} while (0)

-#endif

-

-#define BIGNUM_INT_BYTES (BIGNUM_INT_BITS / 8)

-

-#define BIGNUM_INTERNAL

-typedef BignumInt *Bignum;

-

-#include "ssh.h"

-

-BignumInt bnZero[1] = { 0 };

-BignumInt bnOne[2] = { 1, 1 };

-

-/*

- * The Bignum format is an array of `BignumInt'. The first

- * element of the array counts the remaining elements. The

- * remaining elements express the actual number, base 2^BIGNUM_INT_BITS, _least_

- * significant digit first. (So it's trivial to extract the bit

- * with value 2^n for any n.)

- *

- * All Bignums in this module are positive. Negative numbers must

- * be dealt with outside it.

- *

- * INVARIANT: the most significant word of any Bignum must be

- * nonzero.

- */

-

-Bignum Zero = bnZero, One = bnOne;

-

-static Bignum newbn(int length)

-{

-    Bignum b = snewn(length + 1, BignumInt);

-    if (!b)

-	abort();		       /* FIXME */

-    memset(b, 0, (length + 1) * sizeof(*b));

-    b[0] = length;

-    return b;

-}

-

-void bn_restore_invariant(Bignum b)

-{

-    while (b[0] > 1 && b[b[0]] == 0)

-	b[0]--;

-}

-

-Bignum copybn(Bignum orig)

-{

-    Bignum b = snewn(orig[0] + 1, BignumInt);

-    if (!b)

-	abort();		       /* FIXME */

-    memcpy(b, orig, (orig[0] + 1) * sizeof(*b));

-    return b;

-}

-

-void freebn(Bignum b)

-{

-    /*

-     * Burn the evidence, just in case.

-     */

-    memset(b, 0, sizeof(b[0]) * (b[0] + 1));

-    sfree(b);

-}

-

-Bignum bn_power_2(int n)

-{

-    Bignum ret = newbn(n / BIGNUM_INT_BITS + 1);

-    bignum_set_bit(ret, n, 1);

-    return ret;

-}

-

-/*

- * Compute c = a * b.

- * Input is in the first len words of a and b.

- * Result is returned in the first 2*len words of c.

- */

-static void internal_mul(BignumInt *a, BignumInt *b,

-			 BignumInt *c, int len)

-{

-    int i, j;

-    BignumDblInt t;

-

-    for (j = 0; j < 2 * len; j++)

-	c[j] = 0;

-

-    for (i = len - 1; i >= 0; i--) {

-	t = 0;

-	for (j = len - 1; j >= 0; j--) {

-	    t += MUL_WORD(a[i], (BignumDblInt) b[j]);

-	    t += (BignumDblInt) c[i + j + 1];

-	    c[i + j + 1] = (BignumInt) t;

-	    t = t >> BIGNUM_INT_BITS;

-	}

-	c[i] = (BignumInt) t;

-    }

-}

-

-static void internal_add_shifted(BignumInt *number,

-				 unsigned n, int shift)

-{

-    int word = 1 + (shift / BIGNUM_INT_BITS);

-    int bshift = shift % BIGNUM_INT_BITS;

-    BignumDblInt addend;

-

-    addend = (BignumDblInt)n << bshift;

-

-    while (addend) {

-	addend += number[word];

-	number[word] = (BignumInt) addend & BIGNUM_INT_MASK;

-	addend >>= BIGNUM_INT_BITS;

-	word++;

-    }

-}

-

-/*

- * Compute a = a % m.

- * Input in first alen words of a and first mlen words of m.

- * Output in first alen words of a

- * (of which first alen-mlen words will be zero).

- * The MSW of m MUST have its high bit set.

- * Quotient is accumulated in the `quotient' array, which is a Bignum

- * rather than the internal bigendian format. Quotient parts are shifted

- * left by `qshift' before adding into quot.

- */

-static void internal_mod(BignumInt *a, int alen,

-			 BignumInt *m, int mlen,

-			 BignumInt *quot, int qshift)

-{

-    BignumInt m0, m1;

-    unsigned int h;

-    int i, k;

-

-    m0 = m[0];

-    if (mlen > 1)

-	m1 = m[1];

-    else

-	m1 = 0;

-

-    for (i = 0; i <= alen - mlen; i++) {

-	BignumDblInt t;

-	unsigned int q, r, c, ai1;

-

-	if (i == 0) {

-	    h = 0;

-	} else {

-	    h = a[i - 1];

-	    a[i - 1] = 0;

-	}

-

-	if (i == alen - 1)

-	    ai1 = 0;

-	else

-	    ai1 = a[i + 1];

-

-	/* Find q = h:a[i] / m0 */

-	if (h >= m0) {

-	    /*

-	     * Special case.

-	     * 

-	     * To illustrate it, suppose a BignumInt is 8 bits, and

-	     * we are dividing (say) A1:23:45:67 by A1:B2:C3. Then

-	     * our initial division will be 0xA123 / 0xA1, which

-	     * will give a quotient of 0x100 and a divide overflow.

-	     * However, the invariants in this division algorithm

-	     * are not violated, since the full number A1:23:... is

-	     * _less_ than the quotient prefix A1:B2:... and so the

-	     * following correction loop would have sorted it out.

-	     * 

-	     * In this situation we set q to be the largest

-	     * quotient we _can_ stomach (0xFF, of course).

-	     */

-	    q = BIGNUM_INT_MASK;

-	} else {

-	    /* Macro doesn't want an array subscript expression passed

-	     * into it (see definition), so use a temporary. */

-	    BignumInt tmplo = a[i];

-	    DIVMOD_WORD(q, r, h, tmplo, m0);

-

-	    /* Refine our estimate of q by looking at

-	     h:a[i]:a[i+1] / m0:m1 */

-	    t = MUL_WORD(m1, q);

-	    if (t > ((BignumDblInt) r << BIGNUM_INT_BITS) + ai1) {

-		q--;

-		t -= m1;

-		r = (r + m0) & BIGNUM_INT_MASK;     /* overflow? */

-		if (r >= (BignumDblInt) m0 &&

-		    t > ((BignumDblInt) r << BIGNUM_INT_BITS) + ai1) q--;

-	    }

-	}

-

-	/* Subtract q * m from a[i...] */

-	c = 0;

-	for (k = mlen - 1; k >= 0; k--) {

-	    t = MUL_WORD(q, m[k]);

-	    t += c;

-	    c = (unsigned)(t >> BIGNUM_INT_BITS);

-	    if ((BignumInt) t > a[i + k])

-		c++;

-	    a[i + k] -= (BignumInt) t;

-	}

-

-	/* Add back m in case of borrow */

-	if (c != h) {

-	    t = 0;

-	    for (k = mlen - 1; k >= 0; k--) {

-		t += m[k];

-		t += a[i + k];

-		a[i + k] = (BignumInt) t;

-		t = t >> BIGNUM_INT_BITS;

-	    }

-	    q--;

-	}

-	if (quot)

-	    internal_add_shifted(quot, q, qshift + BIGNUM_INT_BITS * (alen - mlen - i));

-    }

-}

-

-/*

- * Compute (base ^ exp) % mod.

- */

-Bignum modpow(Bignum base_in, Bignum exp, Bignum mod)

-{

-    BignumInt *a, *b, *n, *m;

-    int mshift;

-    int mlen, i, j;

-    Bignum base, result;

-

-    /*

-     * The most significant word of mod needs to be non-zero. It

-     * should already be, but let's make sure.

-     */

-    assert(mod[mod[0]] != 0);

-

-    /*

-     * Make sure the base is smaller than the modulus, by reducing

-     * it modulo the modulus if not.

-     */

-    base = bigmod(base_in, mod);

-

-    /* Allocate m of size mlen, copy mod to m */

-    /* We use big endian internally */

-    mlen = mod[0];

-    m = snewn(mlen, BignumInt);

-    for (j = 0; j < mlen; j++)

-	m[j] = mod[mod[0] - j];

-

-    /* Shift m left to make msb bit set */

-    for (mshift = 0; mshift < BIGNUM_INT_BITS-1; mshift++)

-	if ((m[0] << mshift) & BIGNUM_TOP_BIT)

-	    break;

-    if (mshift) {

-	for (i = 0; i < mlen - 1; i++)

-	    m[i] = (m[i] << mshift) | (m[i + 1] >> (BIGNUM_INT_BITS - mshift));

-	m[mlen - 1] = m[mlen - 1] << mshift;

-    }

-

-    /* Allocate n of size mlen, copy base to n */

-    n = snewn(mlen, BignumInt);

-    i = mlen - base[0];

-    for (j = 0; j < i; j++)

-	n[j] = 0;

-    for (j = 0; j < (int)base[0]; j++)

-	n[i + j] = base[base[0] - j];

-

-    /* Allocate a and b of size 2*mlen. Set a = 1 */

-    a = snewn(2 * mlen, BignumInt);

-    b = snewn(2 * mlen, BignumInt);

-    for (i = 0; i < 2 * mlen; i++)

-	a[i] = 0;

-    a[2 * mlen - 1] = 1;

-

-    /* Skip leading zero bits of exp. */

-    i = 0;

-    j = BIGNUM_INT_BITS-1;

-    while (i < (int)exp[0] && (exp[exp[0] - i] & (1 << j)) == 0) {

-	j--;

-	if (j < 0) {

-	    i++;

-	    j = BIGNUM_INT_BITS-1;

-	}

-    }

-

-    /* Main computation */

-    while (i < (int)exp[0]) {

-	while (j >= 0) {

-	    internal_mul(a + mlen, a + mlen, b, mlen);

-	    internal_mod(b, mlen * 2, m, mlen, NULL, 0);

-	    if ((exp[exp[0] - i] & (1 << j)) != 0) {

-		internal_mul(b + mlen, n, a, mlen);

-		internal_mod(a, mlen * 2, m, mlen, NULL, 0);

-	    } else {

-		BignumInt *t;

-		t = a;

-		a = b;

-		b = t;

-	    }

-	    j--;

-	}

-	i++;

-	j = BIGNUM_INT_BITS-1;

-    }

-

-    /* Fixup result in case the modulus was shifted */

-    if (mshift) {

-	for (i = mlen - 1; i < 2 * mlen - 1; i++)

-	    a[i] = (a[i] << mshift) | (a[i + 1] >> (BIGNUM_INT_BITS - mshift));

-	a[2 * mlen - 1] = a[2 * mlen - 1] << mshift;

-	internal_mod(a, mlen * 2, m, mlen, NULL, 0);

-	for (i = 2 * mlen - 1; i >= mlen; i--)

-	    a[i] = (a[i] >> mshift) | (a[i - 1] << (BIGNUM_INT_BITS - mshift));

-    }

-

-    /* Copy result to buffer */

-    result = newbn(mod[0]);

-    for (i = 0; i < mlen; i++)

-	result[result[0] - i] = a[i + mlen];

-    while (result[0] > 1 && result[result[0]] == 0)

-	result[0]--;

-

-    /* Free temporary arrays */

-    for (i = 0; i < 2 * mlen; i++)

-	a[i] = 0;

-    sfree(a);

-    for (i = 0; i < 2 * mlen; i++)

-	b[i] = 0;

-    sfree(b);

-    for (i = 0; i < mlen; i++)

-	m[i] = 0;

-    sfree(m);

-    for (i = 0; i < mlen; i++)

-	n[i] = 0;

-    sfree(n);

-

-    freebn(base);

-

-    return result;

-}

-

-/*

- * Compute (p * q) % mod.

- * The most significant word of mod MUST be non-zero.

- * We assume that the result array is the same size as the mod array.

- */

-Bignum modmul(Bignum p, Bignum q, Bignum mod)

-{

-    BignumInt *a, *n, *m, *o;

-    int mshift;

-    int pqlen, mlen, rlen, i, j;

-    Bignum result;

-

-    /* Allocate m of size mlen, copy mod to m */

-    /* We use big endian internally */

-    mlen = mod[0];

-    m = snewn(mlen, BignumInt);

-    for (j = 0; j < mlen; j++)

-	m[j] = mod[mod[0] - j];

-

-    /* Shift m left to make msb bit set */

-    for (mshift = 0; mshift < BIGNUM_INT_BITS-1; mshift++)

-	if ((m[0] << mshift) & BIGNUM_TOP_BIT)

-	    break;

-    if (mshift) {

-	for (i = 0; i < mlen - 1; i++)

-	    m[i] = (m[i] << mshift) | (m[i + 1] >> (BIGNUM_INT_BITS - mshift));

-	m[mlen - 1] = m[mlen - 1] << mshift;

-    }

-

-    pqlen = (p[0] > q[0] ? p[0] : q[0]);

-

-    /* Allocate n of size pqlen, copy p to n */

-    n = snewn(pqlen, BignumInt);

-    i = pqlen - p[0];

-    for (j = 0; j < i; j++)

-	n[j] = 0;

-    for (j = 0; j < (int)p[0]; j++)

-	n[i + j] = p[p[0] - j];

-

-    /* Allocate o of size pqlen, copy q to o */

-    o = snewn(pqlen, BignumInt);

-    i = pqlen - q[0];

-    for (j = 0; j < i; j++)

-	o[j] = 0;

-    for (j = 0; j < (int)q[0]; j++)

-	o[i + j] = q[q[0] - j];

-

-    /* Allocate a of size 2*pqlen for result */

-    a = snewn(2 * pqlen, BignumInt);

-

-    /* Main computation */

-    internal_mul(n, o, a, pqlen);

-    internal_mod(a, pqlen * 2, m, mlen, NULL, 0);

-

-    /* Fixup result in case the modulus was shifted */

-    if (mshift) {

-	for (i = 2 * pqlen - mlen - 1; i < 2 * pqlen - 1; i++)

-	    a[i] = (a[i] << mshift) | (a[i + 1] >> (BIGNUM_INT_BITS - mshift));

-	a[2 * pqlen - 1] = a[2 * pqlen - 1] << mshift;

-	internal_mod(a, pqlen * 2, m, mlen, NULL, 0);

-	for (i = 2 * pqlen - 1; i >= 2 * pqlen - mlen; i--)

-	    a[i] = (a[i] >> mshift) | (a[i - 1] << (BIGNUM_INT_BITS - mshift));

-    }

-

-    /* Copy result to buffer */

-    rlen = (mlen < pqlen * 2 ? mlen : pqlen * 2);

-    result = newbn(rlen);

-    for (i = 0; i < rlen; i++)

-	result[result[0] - i] = a[i + 2 * pqlen - rlen];

-    while (result[0] > 1 && result[result[0]] == 0)

-	result[0]--;

-

-    /* Free temporary arrays */

-    for (i = 0; i < 2 * pqlen; i++)

-	a[i] = 0;

-    sfree(a);

-    for (i = 0; i < mlen; i++)

-	m[i] = 0;

-    sfree(m);

-    for (i = 0; i < pqlen; i++)

-	n[i] = 0;

-    sfree(n);

-    for (i = 0; i < pqlen; i++)

-	o[i] = 0;

-    sfree(o);

-

-    return result;

-}

-

-/*

- * Compute p % mod.

- * The most significant word of mod MUST be non-zero.

- * We assume that the result array is the same size as the mod array.

- * We optionally write out a quotient if `quotient' is non-NULL.

- * We can avoid writing out the result if `result' is NULL.

- */

-static void bigdivmod(Bignum p, Bignum mod, Bignum result, Bignum quotient)

-{

-    BignumInt *n, *m;

-    int mshift;

-    int plen, mlen, i, j;

-

-    /* Allocate m of size mlen, copy mod to m */

-    /* We use big endian internally */

-    mlen = mod[0];

-    m = snewn(mlen, BignumInt);

-    for (j = 0; j < mlen; j++)

-	m[j] = mod[mod[0] - j];

-

-    /* Shift m left to make msb bit set */

-    for (mshift = 0; mshift < BIGNUM_INT_BITS-1; mshift++)

-	if ((m[0] << mshift) & BIGNUM_TOP_BIT)

-	    break;

-    if (mshift) {

-	for (i = 0; i < mlen - 1; i++)

-	    m[i] = (m[i] << mshift) | (m[i + 1] >> (BIGNUM_INT_BITS - mshift));

-	m[mlen - 1] = m[mlen - 1] << mshift;

-    }

-

-    plen = p[0];

-    /* Ensure plen > mlen */

-    if (plen <= mlen)

-	plen = mlen + 1;

-

-    /* Allocate n of size plen, copy p to n */

-    n = snewn(plen, BignumInt);

-    for (j = 0; j < plen; j++)

-	n[j] = 0;

-    for (j = 1; j <= (int)p[0]; j++)

-	n[plen - j] = p[j];

-

-    /* Main computation */

-    internal_mod(n, plen, m, mlen, quotient, mshift);

-

-    /* Fixup result in case the modulus was shifted */

-    if (mshift) {

-	for (i = plen - mlen - 1; i < plen - 1; i++)

-	    n[i] = (n[i] << mshift) | (n[i + 1] >> (BIGNUM_INT_BITS - mshift));

-	n[plen - 1] = n[plen - 1] << mshift;

-	internal_mod(n, plen, m, mlen, quotient, 0);

-	for (i = plen - 1; i >= plen - mlen; i--)

-	    n[i] = (n[i] >> mshift) | (n[i - 1] << (BIGNUM_INT_BITS - mshift));

-    }

-

-    /* Copy result to buffer */

-    if (result) {

-	for (i = 1; i <= (int)result[0]; i++) {

-	    int j = plen - i;

-	    result[i] = j >= 0 ? n[j] : 0;

-	}

-    }

-

-    /* Free temporary arrays */

-    for (i = 0; i < mlen; i++)

-	m[i] = 0;

-    sfree(m);

-    for (i = 0; i < plen; i++)

-	n[i] = 0;

-    sfree(n);

-}

-

-/*

- * Decrement a number.

- */

-void decbn(Bignum bn)

-{

-    int i = 1;

-    while (i < (int)bn[0] && bn[i] == 0)

-	bn[i++] = BIGNUM_INT_MASK;

-    bn[i]--;

-}

-

-Bignum bignum_from_bytes(const unsigned char *data, int nbytes)

-{

-    Bignum result;

-    int w, i;

-

-    w = (nbytes + BIGNUM_INT_BYTES - 1) / BIGNUM_INT_BYTES; /* bytes->words */

-

-    result = newbn(w);

-    for (i = 1; i <= w; i++)

-	result[i] = 0;

-    for (i = nbytes; i--;) {

-	unsigned char byte = *data++;

-	result[1 + i / BIGNUM_INT_BYTES] |= byte << (8*i % BIGNUM_INT_BITS);

-    }

-

-    while (result[0] > 1 && result[result[0]] == 0)

-	result[0]--;

-    return result;

-}

-

-/*

- * Read an SSH-1-format bignum from a data buffer. Return the number

- * of bytes consumed, or -1 if there wasn't enough data.

- */

-int ssh1_read_bignum(const unsigned char *data, int len, Bignum * result)

-{

-    const unsigned char *p = data;

-    int i;

-    int w, b;

-

-    if (len < 2)

-	return -1;

-

-    w = 0;

-    for (i = 0; i < 2; i++)

-	w = (w << 8) + *p++;

-    b = (w + 7) / 8;		       /* bits -> bytes */

-

-    if (len < b+2)

-	return -1;

-

-    if (!result)		       /* just return length */

-	return b + 2;

-

-    *result = bignum_from_bytes(p, b);

-

-    return p + b - data;

-}

-

-/*

- * Return the bit count of a bignum, for SSH-1 encoding.

- */

-int bignum_bitcount(Bignum bn)

-{

-    int bitcount = bn[0] * BIGNUM_INT_BITS - 1;

-    while (bitcount >= 0

-	   && (bn[bitcount / BIGNUM_INT_BITS + 1] >> (bitcount % BIGNUM_INT_BITS)) == 0) bitcount--;

-    return bitcount + 1;

-}

-

-/*

- * Return the byte length of a bignum when SSH-1 encoded.

- */

-int ssh1_bignum_length(Bignum bn)

-{

-    return 2 + (bignum_bitcount(bn) + 7) / 8;

-}

-

-/*

- * Return the byte length of a bignum when SSH-2 encoded.

- */

-int ssh2_bignum_length(Bignum bn)

-{

-    return 4 + (bignum_bitcount(bn) + 8) / 8;

-}

-

-/*

- * Return a byte from a bignum; 0 is least significant, etc.

- */

-int bignum_byte(Bignum bn, int i)

-{

-    if (i >= (int)(BIGNUM_INT_BYTES * bn[0]))

-	return 0;		       /* beyond the end */

-    else

-	return (bn[i / BIGNUM_INT_BYTES + 1] >>

-		((i % BIGNUM_INT_BYTES)*8)) & 0xFF;

-}

-

-/*

- * Return a bit from a bignum; 0 is least significant, etc.

- */

-int bignum_bit(Bignum bn, int i)

-{

-    if (i >= (int)(BIGNUM_INT_BITS * bn[0]))

-	return 0;		       /* beyond the end */

-    else

-	return (bn[i / BIGNUM_INT_BITS + 1] >> (i % BIGNUM_INT_BITS)) & 1;

-}

-

-/*

- * Set a bit in a bignum; 0 is least significant, etc.

- */

-void bignum_set_bit(Bignum bn, int bitnum, int value)

-{

-    if (bitnum >= (int)(BIGNUM_INT_BITS * bn[0]))

-	abort();		       /* beyond the end */

-    else {

-	int v = bitnum / BIGNUM_INT_BITS + 1;

-	int mask = 1 << (bitnum % BIGNUM_INT_BITS);

-	if (value)

-	    bn[v] |= mask;

-	else

-	    bn[v] &= ~mask;

-    }

-}

-

-/*

- * Write a SSH-1-format bignum into a buffer. It is assumed the

- * buffer is big enough. Returns the number of bytes used.

- */

-int ssh1_write_bignum(void *data, Bignum bn)

-{

-    unsigned char *p = data;

-    int len = ssh1_bignum_length(bn);

-    int i;

-    int bitc = bignum_bitcount(bn);

-

-    *p++ = (bitc >> 8) & 0xFF;

-    *p++ = (bitc) & 0xFF;

-    for (i = len - 2; i--;)

-	*p++ = bignum_byte(bn, i);

-    return len;

-}

-

-/*

- * Compare two bignums. Returns like strcmp.

- */

-int bignum_cmp(Bignum a, Bignum b)

-{

-    int amax = a[0], bmax = b[0];

-    int i = (amax > bmax ? amax : bmax);

-    while (i) {

-	BignumInt aval = (i > amax ? 0 : a[i]);

-	BignumInt bval = (i > bmax ? 0 : b[i]);

-	if (aval < bval)

-	    return -1;

-	if (aval > bval)

-	    return +1;

-	i--;

-    }

-    return 0;

-}

-

-/*

- * Right-shift one bignum to form another.

- */

-Bignum bignum_rshift(Bignum a, int shift)

-{

-    Bignum ret;

-    int i, shiftw, shiftb, shiftbb, bits;

-    BignumInt ai, ai1;

-

-    bits = bignum_bitcount(a) - shift;

-    ret = newbn((bits + BIGNUM_INT_BITS - 1) / BIGNUM_INT_BITS);

-

-    if (ret) {

-	shiftw = shift / BIGNUM_INT_BITS;

-	shiftb = shift % BIGNUM_INT_BITS;

-	shiftbb = BIGNUM_INT_BITS - shiftb;

-

-	ai1 = a[shiftw + 1];

-	for (i = 1; i <= (int)ret[0]; i++) {

-	    ai = ai1;

-	    ai1 = (i + shiftw + 1 <= (int)a[0] ? a[i + shiftw + 1] : 0);

-	    ret[i] = ((ai >> shiftb) | (ai1 << shiftbb)) & BIGNUM_INT_MASK;

-	}

-    }

-

-    return ret;

-}

-

-/*

- * Non-modular multiplication and addition.

- */

-Bignum bigmuladd(Bignum a, Bignum b, Bignum addend)

-{

-    int alen = a[0], blen = b[0];

-    int mlen = (alen > blen ? alen : blen);

-    int rlen, i, maxspot;

-    BignumInt *workspace;

-    Bignum ret;

-

-    /* mlen space for a, mlen space for b, 2*mlen for result */

-    workspace = snewn(mlen * 4, BignumInt);

-    for (i = 0; i < mlen; i++) {

-	workspace[0 * mlen + i] = (mlen - i <= (int)a[0] ? a[mlen - i] : 0);

-	workspace[1 * mlen + i] = (mlen - i <= (int)b[0] ? b[mlen - i] : 0);

-    }

-

-    internal_mul(workspace + 0 * mlen, workspace + 1 * mlen,

-		 workspace + 2 * mlen, mlen);

-

-    /* now just copy the result back */

-    rlen = alen + blen + 1;

-    if (addend && rlen <= (int)addend[0])

-	rlen = addend[0] + 1;

-    ret = newbn(rlen);

-    maxspot = 0;

-    for (i = 1; i <= (int)ret[0]; i++) {

-	ret[i] = (i <= 2 * mlen ? workspace[4 * mlen - i] : 0);

-	if (ret[i] != 0)

-	    maxspot = i;

-    }

-    ret[0] = maxspot;

-

-    /* now add in the addend, if any */

-    if (addend) {

-	BignumDblInt carry = 0;

-	for (i = 1; i <= rlen; i++) {

-	    carry += (i <= (int)ret[0] ? ret[i] : 0);

-	    carry += (i <= (int)addend[0] ? addend[i] : 0);

-	    ret[i] = (BignumInt) carry & BIGNUM_INT_MASK;

-	    carry >>= BIGNUM_INT_BITS;

-	    if (ret[i] != 0 && i > maxspot)

-		maxspot = i;

-	}

-    }

-    ret[0] = maxspot;

-

-    sfree(workspace);

-    return ret;

-}

-

-/*

- * Non-modular multiplication.

- */

-Bignum bigmul(Bignum a, Bignum b)

-{

-    return bigmuladd(a, b, NULL);

-}

-

-/*

- * Create a bignum which is the bitmask covering another one. That

- * is, the smallest integer which is >= N and is also one less than

- * a power of two.

- */

-Bignum bignum_bitmask(Bignum n)

-{

-    Bignum ret = copybn(n);

-    int i;

-    BignumInt j;

-

-    i = ret[0];

-    while (n[i] == 0 && i > 0)

-	i--;

-    if (i <= 0)

-	return ret;		       /* input was zero */

-    j = 1;

-    while (j < n[i])

-	j = 2 * j + 1;

-    ret[i] = j;

-    while (--i > 0)

-	ret[i] = BIGNUM_INT_MASK;

-    return ret;

-}

-

-/*

- * Convert a (max 32-bit) long into a bignum.

- */

-Bignum bignum_from_long(unsigned long nn)

-{

-    Bignum ret;

-    BignumDblInt n = nn;

-

-    ret = newbn(3);

-    ret[1] = (BignumInt)(n & BIGNUM_INT_MASK);

-    ret[2] = (BignumInt)((n >> BIGNUM_INT_BITS) & BIGNUM_INT_MASK);

-    ret[3] = 0;

-    ret[0] = (ret[2]  ? 2 : 1);

-    return ret;

-}

-

-/*

- * Add a long to a bignum.

- */

-Bignum bignum_add_long(Bignum number, unsigned long addendx)

-{

-    Bignum ret = newbn(number[0] + 1);

-    int i, maxspot = 0;

-    BignumDblInt carry = 0, addend = addendx;

-

-    for (i = 1; i <= (int)ret[0]; i++) {

-	carry += addend & BIGNUM_INT_MASK;

-	carry += (i <= (int)number[0] ? number[i] : 0);

-	addend >>= BIGNUM_INT_BITS;

-	ret[i] = (BignumInt) carry & BIGNUM_INT_MASK;

-	carry >>= BIGNUM_INT_BITS;

-	if (ret[i] != 0)

-	    maxspot = i;

-    }

-    ret[0] = maxspot;

-    return ret;

-}

-

-/*

- * Compute the residue of a bignum, modulo a (max 16-bit) short.

- */

-unsigned short bignum_mod_short(Bignum number, unsigned short modulus)

-{

-    BignumDblInt mod, r;

-    int i;

-

-    r = 0;

-    mod = modulus;

-    for (i = number[0]; i > 0; i--)

-	r = (r * (BIGNUM_TOP_BIT % mod) * 2 + number[i] % mod) % mod;

-    return (unsigned short) r;

-}

-

-#ifdef DEBUG

-void diagbn(char *prefix, Bignum md)

-{

-    int i, nibbles, morenibbles;

-    static const char hex[] = "0123456789ABCDEF";

-

-    debug(("%s0x", prefix ? prefix : ""));

-

-    nibbles = (3 + bignum_bitcount(md)) / 4;

-    if (nibbles < 1)

-	nibbles = 1;

-    morenibbles = 4 * md[0] - nibbles;

-    for (i = 0; i < morenibbles; i++)

-	debug(("-"));

-    for (i = nibbles; i--;)

-	debug(("%c",

-	       hex[(bignum_byte(md, i / 2) >> (4 * (i % 2))) & 0xF]));

-

-    if (prefix)

-	debug(("\n"));

-}

-#endif

-

-/*

- * Simple division.

- */

-Bignum bigdiv(Bignum a, Bignum b)

-{

-    Bignum q = newbn(a[0]);

-    bigdivmod(a, b, NULL, q);

-    return q;

-}

-

-/*

- * Simple remainder.

- */

-Bignum bigmod(Bignum a, Bignum b)

-{

-    Bignum r = newbn(b[0]);

-    bigdivmod(a, b, r, NULL);

-    return r;

-}

-

-/*

- * Greatest common divisor.

- */

-Bignum biggcd(Bignum av, Bignum bv)

-{

-    Bignum a = copybn(av);

-    Bignum b = copybn(bv);

-

-    while (bignum_cmp(b, Zero) != 0) {

-	Bignum t = newbn(b[0]);

-	bigdivmod(a, b, t, NULL);

-	while (t[0] > 1 && t[t[0]] == 0)

-	    t[0]--;

-	freebn(a);

-	a = b;

-	b = t;

-    }

-

-    freebn(b);

-    return a;

-}

-

-/*

- * Modular inverse, using Euclid's extended algorithm.

- */

-Bignum modinv(Bignum number, Bignum modulus)

-{

-    Bignum a = copybn(modulus);

-    Bignum b = copybn(number);

-    Bignum xp = copybn(Zero);

-    Bignum x = copybn(One);

-    int sign = +1;

-

-    while (bignum_cmp(b, One) != 0) {

-	Bignum t = newbn(b[0]);

-	Bignum q = newbn(a[0]);

-	bigdivmod(a, b, t, q);

-	while (t[0] > 1 && t[t[0]] == 0)

-	    t[0]--;

-	freebn(a);

-	a = b;

-	b = t;

-	t = xp;

-	xp = x;

-	x = bigmuladd(q, xp, t);

-	sign = -sign;

-	freebn(t);

-	freebn(q);

-    }

-

-    freebn(b);

-    freebn(a);

-    freebn(xp);

-

-    /* now we know that sign * x == 1, and that x < modulus */

-    if (sign < 0) {

-	/* set a new x to be modulus - x */

-	Bignum newx = newbn(modulus[0]);

-	BignumInt carry = 0;

-	int maxspot = 1;

-	int i;

-

-	for (i = 1; i <= (int)newx[0]; i++) {

-	    BignumInt aword = (i <= (int)modulus[0] ? modulus[i] : 0);

-	    BignumInt bword = (i <= (int)x[0] ? x[i] : 0);

-	    newx[i] = aword - bword - carry;

-	    bword = ~bword;

-	    carry = carry ? (newx[i] >= bword) : (newx[i] > bword);

-	    if (newx[i] != 0)

-		maxspot = i;

-	}

-	newx[0] = maxspot;

-	freebn(x);

-	x = newx;

-    }

-

-    /* and return. */

-    return x;

-}

-

-/*

- * Render a bignum into decimal. Return a malloced string holding

- * the decimal representation.

- */

-char *bignum_decimal(Bignum x)

-{

-    int ndigits, ndigit;

-    int i, iszero;

-    BignumDblInt carry;

-    char *ret;

-    BignumInt *workspace;

-

-    /*

-     * First, estimate the number of digits. Since log(10)/log(2)

-     * is just greater than 93/28 (the joys of continued fraction

-     * approximations...) we know that for every 93 bits, we need

-     * at most 28 digits. This will tell us how much to malloc.

-     *

-     * Formally: if x has i bits, that means x is strictly less

-     * than 2^i. Since 2 is less than 10^(28/93), this is less than

-     * 10^(28i/93). We need an integer power of ten, so we must

-     * round up (rounding down might make it less than x again).

-     * Therefore if we multiply the bit count by 28/93, rounding

-     * up, we will have enough digits.

-     *

-     * i=0 (i.e., x=0) is an irritating special case.

-     */

-    i = bignum_bitcount(x);

-    if (!i)

-	ndigits = 1;		       /* x = 0 */

-    else

-	ndigits = (28 * i + 92) / 93;  /* multiply by 28/93 and round up */

-    ndigits++;			       /* allow for trailing \0 */

-    ret = snewn(ndigits, char);

-

-    /*

-     * Now allocate some workspace to hold the binary form as we

-     * repeatedly divide it by ten. Initialise this to the

-     * big-endian form of the number.

-     */

-    workspace = snewn(x[0], BignumInt);

-    for (i = 0; i < (int)x[0]; i++)

-	workspace[i] = x[x[0] - i];

-

-    /*

-     * Next, write the decimal number starting with the last digit.

-     * We use ordinary short division, dividing 10 into the

-     * workspace.

-     */

-    ndigit = ndigits - 1;

-    ret[ndigit] = '\0';

-    do {

-	iszero = 1;

-	carry = 0;

-	for (i = 0; i < (int)x[0]; i++) {

-	    carry = (carry << BIGNUM_INT_BITS) + workspace[i];

-	    workspace[i] = (BignumInt) (carry / 10);

-	    if (workspace[i])

-		iszero = 0;

-	    carry %= 10;

-	}

-	ret[--ndigit] = (char) (carry + '0');

-    } while (!iszero);

-

-    /*

-     * There's a chance we've fallen short of the start of the

-     * string. Correct if so.

-     */

-    if (ndigit > 0)

-	memmove(ret, ret + ndigit, ndigits - ndigit);

-

-    /*

-     * Done.

-     */

-    sfree(workspace);

-    return ret;

-}